ATOMIC SCALE STUDY ON STRUCTURE AND BEHAVIOR OF ELEMENTS IN AMORPHOUS ALLOYS

为了弄清非晶结构和结晶核结构的真实面貌，利用原子探针场离子显微镜在原子尺度上进行了研究。本研究使用的合金是Pd-16at%Si和Pd-16at%Si-9at%Cu合金，其电子衍射图在凝固状态下显示晕环。首先，建立了原子探针数据的统计分析方法。接下来，使用上述方法对结构进行了分析。结果表明，两种合金均存在浓度波动。在Pd-Si合金和Pd-Si- cu合金中，其Si含量分别为8-24at%和8-40at%。Cu的加入使浓度波动范围扩大。Pd-Si合金中存在浓度波动的周期性，而Pd-Si- cu合金中没有。在Pd-Si-Cu合金中，Cu原子与Pd和Si原子形成1 ~ 3的团簇。这种团簇可以稳定加入Cu原子的合金的非晶结构。上述分析方法对于解决合金中的原子尺度结构是非常有效的。

In order to made clear the true picture of amorphous structure and the structure of nuclei of crystalline a study in an atomic scale has been made by atom-probe field-ion microscope. Alloys used in the present study are Pd-16at%Si and Pd-16at%Si-9at%Cu alloys whose electron diffraction patterns show halo ring in their solidified state.First, methods for statistical analyses of aton-probe data have been established. Next, the structure has been analyzed using the above methods. It is found that concentration fluctuation exists in the both alloys. It extends in the range of 8-24at%Si in the Pd-Si alloy and of 8-40at% Si in the Pd-Si-Cu alloy. Cu addition forces a range of concentration fluctuation to extend. The periodicity in the concentration fluctuation is found in the Pd-Si alloy, but not in the Pd-Si-Cu alloy. In the Pd-Si-Cu alloy Cu atoms form clusters with Pd and Si atoms of one to three. Such clusters may stabilize amorphous structure in the alloy that Cu atoms are added.The above analysis methods are quite effective to solve the atomic scale structure in alloy.